![spears and munsil black levels on projector spears and munsil black levels on projector](https://www.projectorreviews.com/wp-content/uploads/2017/09/Pro-Cinema-4040_hunger-games-Katniss-interview.jpg)
If more contrast is better, why not take it all the way up to the maximum possible? The basic reason is simple: because most displays will distort in some way well before the Contrast control reaches maximum. This immediately raises the question of why you’d ever want to do anything other than cranking Contrast all the way up. At some point there is a law of diminishing returns, but broadly speaking a higher contrast ratio is better. People talk about images “popping off the screen,” and most of that effect is contrast. That said, increasing the contrast further makes images look punchier and more realistic. Printed photographs, for example, typically have a contrast no greater than 100:1, which most people find reasonable. It’s not absolutely necessary to meet that level of contrast to produce acceptable images. Your eyes can detect a ratio of 10,000:1 in the same scene under ideal conditions, and at least 1000:1 under less ideal conditions. If you compare the effects of change Brightness to changing Contrast you’ll note that the Contrast control raises and lowers the level of the brightest parts of the image, but leaves the dark areas mostly unchanged.Ĭontrast is central to perceived quality in all forms of image reproduction. The following image is the same one used in the article about the Brightness control. And because the black level didn’t change, and the real practical “black” on the screen is never really absolute black, by raising the white level you also raise the contrast. And all the levels in between 0 and 100% just move up proportionally, leaving the overall image looking essentially the same, but brighter. This is handy, because it allows you to raise and lower the highest brightness level (the “white level” we mentioned before) without changing the black level, because 0 multiplied by anything is still 0. The result is that if you raise the Contrast control, the brightest parts of the screen get much brighter, the medium-bright sections get somewhat brighter, and the darkest parts don’t change much at all. It multiplies all the light levels on the screen by some amount near 1.0. Contrast, on the other hand, is a multiplier. Raising the Brightness control is the equivalent of adding light to every part of the screen equally. As mentioned in our previous article, the Brightness control adds or subtracts some amount to/from the onscreen levels. Since the residual black level is usually close to constant, raising the white level also raises the overall contrast ratio, which is the basic reason the control is called “contrast.”įirst consider the Brightness control. Even if the display itself doesn’t produce any light, there’s always some amount of ambient light or light reflected from the brighter parts of the image off the walls of the room and back onto the screen. In practice, all real displays have some residual brightness even when they’re supposed to be showing black. In theory, the black level is supposed to be absolute black (0 luminance), which would result in an undefined, or “infinity:1” contrast level. It’s almost always given in ratio form with “1” as the denominator, as in “100:1” or “1000:1”. To understand the name, let’s start by defining “contrast.” In the video realm, contrast is the ratio between a bright reference value (“white level”) and a dark reference value (“black level”). Another word for “luminance” is “brightness,” which is why it’s confusing that the control is called “contrast” and not “brightness,” but those are the names the original video engineers gave the controls. The Contrast control is used to set the overall luminance of the display to the appropriate level. If you just want the detailed instructions, skip ahead to the section called “Using the Contrast Pattern.” If you want all the nitty-gritty of history and theory, read on.